Etching of SiO{sub 2} in C{sub 4}F{sub 8}/Ar plasmas. II. Simulation of surface roughening and local polymerization

Journal Article · Mon Mar 15 04:00:00 EDT 2010 · Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films

DOI:https://doi.org/10.1116/1.3290766· OSTI ID:22051143

Wei, Guo; Sawin, Herbert H ^[1]

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1. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

In this article the SiO{sub 2} surface morphology in C{sub 4}F{sub 8}/Ar plasma etching was simulated using a three-dimensional Monte Carlo profile simulator. The complete surface kinetics model was previously developed, incorporated, and tested for accuracy within the simulator as reported in the companion paper [Guo et al., J. Vac. Sci. Technol. A 28, 250 (2010)]. The simulated planar surface roughening at ion incidence angles from 0 deg. to 82 deg. and flux ratios of 5 and 20 were compared to the experimental results that were etched in reactive ion beam experiments and characterized by atomic force microscopy. Distinctively different patterns were obtained with varying ion incidence angle. The surface remained smooth at normal ion incidence up to 45 deg. off-normal and transformed to striations perpendicular to the ion beam at 60 deg. -75 deg. The transverse striation was explained with the local curvature dependence based on the sputtering theory. The surface became smooth again at grazing angle of 82 deg. The simulated transition of surface morphology was qualitatively consistent with the experimental observations. Surface composition was mapped out to disclose the roughening mechanism. At low flux ratio, the surface composition indicated the formation of polymer islands around the roughened area. Greater polymer formation on the shadowed edge of features and enhanced the roughening, in agreement with the micromasking mechanism proposed previously based on other experimental observations. At high flux ratio, the simulation showed a higher extent of polymerization with a uniform distribution. The surface passivation together with other factors led to a smooth surface. The simulated polymer distribution provided insights to the surface roughening process.

• OSTI ID: 22051143
• Journal Information: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Journal Name: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films Journal Issue: 2 Vol. 28; ISSN 1553-1813
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACCURACY
ATOMIC FORCE MICROSCOPY
CARBON COMPOUNDS
COMPUTERIZED SIMULATION
ETCHING
EXPERIMENTAL DATA
INCIDENCE ANGLE
ION BEAMS
MONTE CARLO METHOD
MORPHOLOGY
PASSIVATION
PLASMA
POLYMERIZATION
POLYMERS
SILICON OXIDES
SPUTTERING
STRIATIONS
SURFACES
THREE-DIMENSIONAL CALCULATIONS